Dynamic logical storage capacity adjustment for storage drives

ABSTRACT

A method for dynamically altering logical storage capacity within multiple storage drives is disclosed. In one embodiment, such a method monitors, within a storage environment, characteristics (e.g., age, wear, etc.) of multiple storage drives. Each storage drive has an amount of overprovisioning associated therewith. Based on the characteristics, the method periodically modifies a logical storage capacity of the storage drives in order to alter the amount of overprovisioning. The method then reorganizes the storage drives within various storage groups (e.g., RAID arrays, storage tiers, workloads, etc.) based on their logical storage capacity. For example, the method may place, as much as possible, storage drives of the same logical storage capacity within the same storage groups. A corresponding system and computer program product are also disclosed.

BACKGROUND Field of the Invention

This invention relates to systems and methods to dynamically compensatefor age and/or wear on storage drives.

Background of the Invention

A RAID (i.e., a Redundant Array of Independent Disks) is a storagetechnology that provides increased storage functions and reliabilitythrough redundancy. A RAID is created by combining multiple storagedrive components (e.g., disk drives and/or solid state drives) into alogical unit. Data is then distributed across the drives using varioustechniques, referred to as “RAID levels.” The standard RAID levels,which currently include RAID levels 1 through 6, are a basic set of RAIDconfigurations that employ striping, mirroring, and/or parity to providedata redundancy. Each of the configurations provides a balance betweentwo key goals: (1) increasing data reliability and (2) increasing I/Operformance.

When storage drives in a RAID are new, the storage drives may havecertain performance characteristics or specifications. Thesecharacteristics or specifications may be expressed in terms of aperformance class, writes-per-day classification, storage capacity,amount of over-provisioning, or the like. Nevertheless, as the storagedrives age and wear out, the storage drives may be unable to provide thesame performance characteristics or specifications that they were ableto provide when new. This may make the storage drives unsuitable for usein certain RAID arrays, storage tiers, or workloads, which may havecertain performance requirements. If the wear or age of the storagedrives is ignored and the same workload is driven to these storagedrives regardless of their age and/or wear, the storage drives mayexhibit excessively high failure rates and/or reduced life cycles.

In view of the foregoing, what are needed are systems and methods todynamically compensate for age and/or wear on storage drives. Ideally,such systems and methods will, based on the age and/or wear of thestorage drives, periodically reassign the storage drives to appropriateRAID arrays, storage tiers, or workloads. Such systems and methods willalso ideally reduce failure rates and increase the useful life of thestorage drives.

SUMMARY

The invention has been developed in response to the present state of theart and, in particular, in response to the problems and needs in the artthat have not yet been fully solved by currently available systems andmethods. Accordingly, embodiments of the invention have been developedto dynamically compensate for age and/or wear on storage drives. Thefeatures and advantages of the invention will become more fully apparentfrom the following description and appended claims, or may be learned bypractice of the invention as set forth hereinafter.

Consistent with the foregoing, a method for dynamically altering logicalstorage capacity within multiple storage drives is disclosed. In oneembodiment, such a method monitors, within a storage environment,characteristics (e.g., age, wear, etc.) of multiple storage drives. Eachstorage drive has an amount of overprovisioning associated therewith.Based on the characteristics, the method periodically modifies a logicalstorage capacity of the storage drives in order to alter the amount ofoverprovisioning. The method then reorganizes the storage drives withinvarious storage groups (e.g., RAID arrays, storage tiers, workloads,etc.) based on their logical storage capacity. For example, the methodmay place, as much as possible, storage drives of the same logicalstorage capacity within the same storage groups.

A corresponding system and computer program product are also disclosedand claimed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limiting of its scope, the invention will be describedand explained with additional specificity and detail through use of theaccompanying drawings, in which:

FIG. 1 is a high-level block diagram showing one example of a networkenvironment in which systems and methods in accordance with theinvention may be implemented;

FIG. 2 is a high-level block diagram showing one embodiment of a storagesystem in which one or more RAIDs or storage tiers may be implemented;

FIG. 3 is a high-level block diagram showing various storage drives andtheir associated performance class when new;

FIG. 4 is a high-level block diagram showing reduction of the storagedrives' performance class as the storage drives age;

FIG. 5 is a high-level block diagram showing reorganization of thestorage drives within RAIDs based on their performance class;

FIG. 6 is a high-level block diagram showing reorganization of thestorage drives within RAIDs based on their writes-per-dayclassification;

FIG. 7 is a high-level block diagram showing reorganization of thestorage drives within RAIDs based on their logical storage capacity;

FIG. 8 is a high-level block diagram showing various sub-modules withina drive monitoring module in accordance with the invention;

FIG. 9 is a high-level block diagram showing various sub-modules withina reclassification module in accordance with the invention;

FIG. 10 is a flow diagram showing one embodiment of a method forreorganizing storage drives based on drive characteristics;

FIG. 11 is a flow diagram showing one embodiment of a method forreorganizing storage drives based on their performance class;

FIG. 12 is a flow diagram showing one embodiment of a method forreorganizing storage drives based on their writes-per-dayclassification; and

FIG. 13 is a flow diagram showing one embodiment of a method forreorganizing storage drives based on their logical storage capacity.

DETAILED DESCRIPTION

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the Figures herein,could be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description of theembodiments of the invention, as represented in the Figures, is notintended to limit the scope of the invention, as claimed, but is merelyrepresentative of certain examples of presently contemplated embodimentsin accordance with the invention. The presently described embodimentswill be best understood by reference to the drawings, wherein like partsare designated by like numerals throughout.

The present invention may be embodied as a system, method, and/orcomputer program product. The computer program product may include acomputer readable storage medium (or media) having computer readableprogram instructions thereon for causing a processor to carry outaspects of the present invention.

The computer readable storage medium may be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage system, a magnetic storage system,an optical storage system, an electromagnetic storage system, asemiconductor storage system, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagesystem via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages.

The computer readable program instructions may execute entirely on auser's computer, partly on a user's computer, as a stand-alone softwarepackage, partly on a user's computer and partly on a remote computer, orentirely on a remote computer or server. In the latter scenario, aremote computer may be connected to a user's computer through any typeof network, including a local area network (LAN) or a wide area network(WAN), or the connection may be made to an external computer (forexample, through the Internet using an Internet Service Provider). Insome embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention may be described herein with referenceto flowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, may be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus, or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

Referring to FIG. 1, one example of a network environment 100 isillustrated. The network environment 100 is presented to show oneexample of an environment where systems and methods in accordance withthe invention may be implemented. The network environment 100 ispresented by way of example and not limitation. Indeed, the systems andmethods disclosed herein may be applicable to a wide variety ofdifferent network environments in addition to the network environment100 shown.

As shown, the network environment 100 includes one or more computers102, 106 interconnected by a network 104. The network 104 may include,for example, a local-area-network (LAN) 104, a wide-area-network (WAN)104, the Internet 104, an intranet 104, or the like. In certainembodiments, the computers 102, 106 may include both client computers102 and server computers 106 (also referred to herein as “hosts” 106 or“host systems” 106). In general, the client computers 102 initiatecommunication sessions, whereas the server computers 106 wait for andrespond to requests from the client computers 102. In certainembodiments, the computers 102 and/or servers 106 may connect to one ormore internal or external direct-attached storage systems 112 (e.g.,arrays of hard-storage drives, solid-state drives, tape drives, etc.).These computers 102, 106 and direct-attached storage systems 112 maycommunicate using protocols such as ATA, SATA, SCSI, SAS, Fibre Channel,or the like.

The network environment 100 may, in certain embodiments, include astorage network 108 behind the servers 106, such as astorage-area-network (SAN) 108 or a LAN 108 (e.g., when usingnetwork-attached storage). This network 108 may connect the servers 106to one or more storage systems 110, such as arrays 110 a of hard-diskdrives or solid-state drives, tape libraries 110 b, individual hard-diskdrives 110 c or solid-state drives 110 c, tape drives 110 d, CD-ROMlibraries, or the like. To access a storage system 110, a host system106 may communicate over physical connections from one or more ports onthe host 106 to one or more ports on the storage system 110. Aconnection may be through a switch, fabric, direct connection, or thelike. In certain embodiments, the servers 106 and storage systems 110may communicate using a networking standard such as Fibre Channel (FC)or iSCSI.

Referring to FIG. 2, one example of a storage system 110 a containing anarray of hard-disk drives 204 and/or solid-state drives 204 isillustrated. The internal components of the storage system 110 a areshown since RAID arrays may, in certain embodiments, be implemented allor partly within such a storage system 110 a. As shown, the storagesystem 110 a includes a storage controller 200, one or more switches202, and one or more storage drives 204, such as hard-disk drives 204and/or solid-state drives 204 (e.g., flash-memory-based drives 204). Thestorage controller 200 may enable one or more host systems 106 (e.g.,open system and/or mainframe servers 106 running operating systems suchz/OS, zVM, or the like) to access data in the one or more storage drives204.

In selected embodiments, the storage controller 200 includes one or moreservers 206 a, 206 b. The storage controller 200 may also include hostadapters 208 and device adapters 210 to connect the storage controller200 to host systems 106 and storage drives 204, respectively. Multipleservers 206 a, 206 b may provide redundancy to ensure that data isalways available to connected host systems 106. Thus, when one server206 a fails, the other server 206 b may pick up the I/O load of thefailed server 206 a to ensure that I/O is able to continue between thehost systems 106 and the storage drives 204. This process may bereferred to as a “failover.”

In selected embodiments, each server 206 includes one or more processors212 and memory 214. The memory 214 may include volatile memory (e.g.,RAM) as well as non-volatile memory (e.g., ROM, EPROM, EEPROM, harddisks, flash memory, etc.). The volatile and non-volatile memory may, incertain embodiments, store software modules that run on the processor(s)212 and are used to access data in the storage drives 204. Thesesoftware modules may manage all read and write requests to logicalvolumes in the storage drives 204.

One example of a storage system 110 a having an architecture similar tothat illustrated in FIG. 2 is the IBM DS8000™ enterprise storage system.The DS8000™ is a high-performance, high-capacity storage controllerproviding disk and solid-state storage that is designed to supportcontinuous operations. Nevertheless, the techniques disclosed herein arenot limited to the IBM DS8000™ enterprise storage system 110 a, but maybe implemented in any comparable or analogous storage system 110,regardless of the manufacturer, product name, or components or componentnames associated with the system 110. Any storage system that couldbenefit from one or more embodiments of the invention is deemed to fallwithin the scope of the invention. Thus, the IBM DS8000™ is presentedonly by way of example and not limitation.

Referring to FIG. 3, in certain embodiments, storage drives 204 of thestorage system 110 a may be configured in one or more RAID arrays 304 toprovide desired levels of reliability and/or I/O performance. A RAIDarray 304 is created by combining multiple storage drive components(e.g., disk drives 204 and/or solid state drives 204) into a logicalunit. Data is then distributed across the drives using varioustechniques, referred to as “RAID levels.” The standard RAID levels,which currently include RAID levels 1 through 6, are a basic set of RAIDconfigurations that employ striping, mirroring, and/or parity to providedata redundancy. Each of the configurations provides a balance betweentwo key goals: (1) increasing data reliability and (2) increasing I/Operformance.

When storage drives 204 in a RAID array 304 are new, the storage drives204 may have certain performance characteristics or specifications.These characteristics or specifications may be expressed in terms of aperformance class, writes-per-day classification, storage capacity,amount of over-provisioning, or the like. Nevertheless, as the storagedrives 204 age and wear out, the storage drives 204 may be unable toprovide the same performance characteristics or specifications that theywere able to provide when new. This may make the storage drives 204unsuitable for use in certain RAID arrays 304, storage tiers, orworkloads, which may have certain performance requirements. If the wearor age of the storage drives 204 is ignored and the same workload isdriven to these storage drives 204 regardless of their age and/or wear,the storage drives 204 may exhibit excessively high failure rates and/orreduced life cycles.

Thus, systems and methods are needed to dynamically compensate for ageand/or wear on storage drives 204. Ideally, such systems and methodswill, based on the age and/or wear of the storage drives 204,periodically reassign the storage drives 204 to appropriate RAID arrays304, storage tiers, or workloads. Such systems and methods will alsoideally reduce failure rates and increase the useful life of the storagedrives 204.

As shown in FIG. 3, when storage drives 204 are new, the new storagedrives 204 may have a certain performance class associated therewith.For example, the storage drives 204 have be assigned performance classA, B, or C, where the performance class A has better performance (e.g.,I/O performance) than the performance class B, and the performance classB has better performance than the performance class C. In theillustrated embodiment, each of the RAID arrays 304 start with storagedrives 204 of the same performance class (in this example, performanceclass A) although this is not necessary in all embodiments. For example,some RAID arrays 304 may be assigned storage drives 204 of a lesserperformance class (e.g., performance class B or C) depending on theperformance requirements of the RAID array 304.

Over time, due to failures and replacement of certain storage drives 204within the RAID arrays 304, the RAID arrays 304 may be made up ofstorage drives 204 having different age and/or wear characteristics.Nevertheless, as the storage drives 204 age and wear out, the storagedrives 204 may be unable to provide the same performance characteristicsor specifications, or be unable to do so without exhibiting higher thanacceptable failure rates or a reduced life cycle. Nevertheless, as thestorage drives 204 of a certain performance class age and/or wear out,the storage drives 204 may continue to be used in the same way as resultof their initially assigned performance class.

In certain embodiments, systems and methods in accordance with theinvention may monitor characteristics (e.g., age and/or wear) of storagedrives 204 in a storage environment and periodically reclassify thestorage drives 204 with an appropriate performance class. For example,for storage drives 204 with an expected life of three years, the storagedrives 204 may initially be assigned performance class A. After thefirst year of use, the storage drives 204 may be reduced to performanceclass B. After the second year of use, the storage drives 204 may bereduced to performance class C. Each time the storage drives 204 areassigned a new performance class, the storage drives 204 may, if notalready, be placed in appropriate storage groups (e.g., RAID arrays 304,storage tiers in a tiered storage environment, storage drives 204 withparticular workload requirements, etc.). This may be accomplished byswapping, in a storage environment, storage drives 204 of a certainperformance class with storage drives 204 of a different performanceclass so that storage groups (e.g., RAID arrays 304, storage tiers,workloads, etc.) contain, as much as possible, storage drives 204 of thesame performance class.

As shown in FIG. 3, in certain embodiments, one or more modules 300,302, 303, may be used to provide various features and functions inaccordance with the invention. For example, a drive monitoring module300 may be configured to monitor storage drive characteristics, such asstorage drive age, use, and/or wear. A drive reclassification module302, by contrast, may be configured to periodically reclassify storagedrives 204 in accordance with their characteristics. For example, thedrive reclassification module 302 may reduce the performance class of astorage drive 204 as it ages or wears out. Once the storage drives 204are reclassified, the drive reorganization module 303 may be configuredto reorganize the storage drive 204 in the storage environment inaccordance with their classification. For example, in certainembodiments, the drive reorganization module 303 may place, as much aspossible, storage drives 204 of the same performance class in the samestorage groups, such as in the same RAID arrays 304 or the same storagetiers.

FIG. 4 shows the RAID arrays 304 of FIG. 3 after the storage drives 204have been reclassified by the drive reclassification module 302. Asshown, after some time has passed and various storage drives 204 withinthe RAID arrays 304 have been replaced or swapped with other storagedrives 204 of the same or different performance class, the storagedrives 204 in the RAID arrays 304 may have different age and/or wearcharacteristics. Based on these age and/or wear characteristics, thedrive reclassification module 302 may modify the performance class ofthe storage drives 204 to reflect their age and/or wear. For example, asshown in FIG. 4, the storage environment may contain storage drives 204that are classified as performance class A, B, or C based on theirmanufacturer specification or their age and/or wear. This creates ascenario where RAID arrays 304 contain storage drives 204 of differingperformance classes, as shown in FIG. 4. In certain embodiments, thestorage drive 204 having the lowest performance class may define theperformance of the entire RAID array 304. That is, a RAID array 304 mayonly be able to perform as well as its lowest performing storage drive204 (i.e., the storage drive 204 with the lowest performance class).Thus, to maximize the performance of a RAID array 304, the RAID array304 will ideally contain storage drives 204 having the same performanceclass.

Referring to 5, in order to accomplish this, once the drivereclassification module 302 has modified the performance class of thestorage drives 204 to conform to their age and/or wear, the drivereorganization module 303 may reorganize the storage drives 204 withinthe storage environment. More particularly, the drive reorganizationmodule 303 may attempt to place storage drives 204 of the sameperformance class in the same RAID arrays 304. Higher performance RAIDarrays 304 will ideally contain storage drives 204 of a higherperformance class. Similarly, lower performance RAID arrays 304 maycontain storage drives 204 of a lower performance class.

In order to reorganize the storage drives 204, the drive reorganizationmodule 303 may swap storage drives 204 between RAID arrays 304 using,for example, a spare storage drive 204 as an intermediate data store tofacilitate the swap of data. In certain embodiments, this isaccomplished using a smart rebuild process to copy data from one storagedrive 204 to another. The smart rebuild process may reduce exposure todata loss by maintaining the ability for a storage drive 204 to be usedas a spare even as data is being copied to it. In certain embodiments,when data is copied from a first storage drive 204 to a second storagedrive 204 (e.g., a spare storage drive 204), the smart rebuild processmay create a bitmap for the first storage drive 204. Each bit mayrepresent a section (e.g., a one megabyte region) of storage space onthe first storage drive 204. The smart rebuild process may then begincopying data from the first storage drive 204 to the second storagedrive 204. As each section is copied, its associated bit may be recordedin the bitmap.

If a write is received to a section of the first storage drive 204 whilethe data copy process is ongoing, the smart rebuild process may checkthe bitmap to determine if data in the associated section has alreadybeen copied to the second storage drive 204. If not, the smart rebuildprocess may simply write the data to the corresponding section of thefirst storage drive 204. Otherwise, after writing the data to the firststorage drive 204, the data may also be copied to the second storagedrive 204. Once all sections are copied from the first storage drive 204to the second storage drive 204, the RAID array 304 may begin to use thesecond storage drive 204 in place of the first storage drive 204. Thisfrees the first storage drive 204 from the RAID array 304.

Alternatively, the smart rebuild process may utilize a watermark insteadof a bitmap to track which data has been copied from a first storagedrive 204 to a second storage drive 204. In such an embodiment, sectionsmay be copied in a designated order from a first storage drive 204 to asecond storage drive 204. The watermark may track how far the copyprocess has progressed through the sections. If a write is received to asection of the first storage drive 204 during the copy process, thesmart rebuild process may check the watermark to determine if data inthe section has already been copied to the second storage drive 204. Ifnot, the smart rebuild process may write the data to the first storagedrive 204. Otherwise, after writing the data to the first storage drive204, the smart rebuild process may also copy the data to the secondstorage drive 204. Once all sections have been copied from the firststorage drive 204 to the second storage drive 204, the RAID array 304may begin to use the second storage drive 204 in place of the firststorage drive 204. This frees the first storage drive 204 from the RAIDarray 304.

In other embodiments, the drive reclassification module 302 may changeother characteristics of storage drives 204 within a storageenvironment. For example, the drive reclassification module 302 maymodify, based on the age or wear of a storage drive 204, awrites-per-day classification, a logical storage capacity, and/or anamount of overprovisioning associated with a storage drive 204. Thedrive reorganization module 303 may then reorganize the storage drives204 within RAID arrays 304 based on their writes-per-day classification,as shown in FIG. 6, or their logical storage capacity, as shown in FIG.7. Thus, systems and methods in accordance with the invention maymonitor various characteristics of storage drives 204, reclassify thestorage drives 204 based on their characteristics, and reorganize thestorage drives 204 after they have been reclassified. The manner inwhich this may be accomplished will be described in more detail inassociation with FIGS. 8 through 13.

FIG. 8 is a high-level block diagram showing various sub-modules thatmay be included within a drive monitoring module 300. The drivemonitoring module 300 and associated sub-modules may be implemented inhardware, software, firmware, or combinations thereof. The drivemonitoring module 300 and associated sub-modules are presented by way ofexample and not limitation. More or fewer sub-modules may be provided indifferent embodiments. For example, the functionality of somesub-modules may be combined into a single or smaller number ofsub-modules, or the functionality of a single sub-module may bedistributed across several sub-modules.

As shown, the drive monitoring module 300 includes one or more of an agemonitoring module 800, wear monitoring module 802, and overprovisioningmonitoring module 804. The age monitoring module 800 may be configuredto monitor the age of storage drives 204 in a storage environment. Incertain embodiments, this may be accomplished by detecting when astorage drive 204 is newly installed in the storage environment and thentracking the amount of time the storage drive 204 is in the storageenvironment from that point forward.

The wear monitoring module 802, by contrast, may monitor the wear ofstorage drives 204 in the storage environment. In certain embodiments,wear may be determined from the use of a storage drive 204, such as theamount of I/O that has been driven to the storage drive 204 over itslifetime, the amount of time the storage drive 204 has been active, thestorage group (e.g., RAID array 304, storage tier, or workload) thestorage drive 204 has been associated with during its use, and/or thelike.

The overprovisioning monitoring module 804 may be configured to monitoran amount of overprovisioning that exists within a storage drive 204.Certain storage drives 204, such as solid state storage drives 204(SSDs), may have a certain percentage of their total storage capacitydedicated to storing data and the remaining percentage kept free in theform of “overprovisioning.” This overprovisioning typically improvesperformance and increases the life of the solid state storage drive 204.As the solid state storage drive 204 ages and/or wears out, storageelements within the solid state storage drive 204 may go bad, which mayin turn reduce the amount of overprovisioning within the storage drive204. This may reduce the performance and/or life of the solid statestorage drive 204.

FIG. 9 is a high-level block diagram showing various sub-modules thatmay be included within the drive reclassification module 302 previouslydescribed. As shown, the drive reclassification module 302 may includeone or more of a performance-class adjustment module 900, writes-per-dayadjustment module 902, and size/overprovisioning adjustment module 904.The performance-class adjustment module 900 may be configured to adjustthe performance class of a storage drive 204 depending oncharacteristics (e.g., age and/or wear) of the storage drive 204 thatare detected by the drive monitoring module 300. In certain embodiments,the performance-class adjustment module 900 may adjust the performanceclass in various discrete steps. For example, the performance-classadjustment module 900 may reduce the performance class from performanceclass A to performance class B, and from performance class B toperformance class C, depending on the age or wear of the storage drive204.

The writes-per-day adjustment module 902 may be used to adjust awrites-per-day classification associated with a storage drive 204. Basedon the age, wear, and/or amount of overprovisioning that is associatedwith a storage drive 204, the writes-per-day adjustment module 902 mayreduce the writes-per-day classification associated with a storage drive204. In certain embodiments, this may occur in discrete steps. Forexample, the writes-per-day classification may drop from a first level(e.g., 200 GB/day) to a second level (150 GB/day), and then from thesecond level to a third level (e.g., 100 GB/day), and so forth, invarious discrete steps depending on the characteristics (e.g., amount ofoverprovisioning, age, etc.) associated with the storage drive 204.

The size/overprovisioning adjustment module 904 may be configured toadjust a logical storage capacity and/or amount of overprovisioningassociated with a storage drive 204. As mentioned above, as a storagedrive 204 (e.g., a solid state storage drive 204) ages or is utilized,sectors or storage elements in the storage drive 204 may go bad. Whenthe amount of overprovisioning within the storage drive 204 is reducedto a certain level or threshold, the size/overprovisioning adjustmentmodule 904 may adjust the logical storage capacity and/or amount ofoverprovisioning in the storage drive 204. For example, thesize/overprovisioning adjustment module 904 may reduce the logicalstorage capacity of the storage drive 204 in order to increase theamount of overprovisioning. This may improve performance and/or increasethe useful life of the storage drive 204. In certain embodiments, thismay occur in various discrete steps. For example, thesize/overprovisioning adjustment module 904 may reduce the logicalstorage capacity of the storage drive 204 from size A (e.g., 900 GB) tosize B (e.g., 800 GB), from size B to size C (e.g., 700 GB), and soforth, in various discrete steps as the storage drive 204 ages and/orwears out. As will be explained in more detail hereafter, in certaincases, when the logical storage capacity of a storage drive 204 isreduced, some data may need to be migrated off of the storage drive 204to facilitate the reduction of logical storage capacity.

Referring to FIG. 10, a flow diagram showing one embodiment of a method1000 for reorganizing storage drives 204 based on drive characteristicsis illustrated. This method 1000 is intended to broadly encompass themore particular methods illustrated in FIGS. 11 through 13.

As shown, the method 1000 initially determines 1002 whether it is timeto reclassify and reorganize storage drives 204 within a storageenvironment. In certain embodiments, the method 1000 is intended to beexecuted periodically, such as every week, every month, or every severalmonths. The step 1002 may be configured to determine if and when themethod 1000 should be executed.

If it is time to reclassify and reorganize storage drives 204 within thestorage environment, the method 1000 determines 1004 drivecharacteristics, such as the age, wear, amount of overprovisioning, orthe like, of the storage drives 204 in the storage environment. Incertain embodiments, the method 1000 actually modifies drivecharacteristics once certain characteristics are observed. For example,in the event the amount of overprovisioning in a storage drive 204 dropsbelow a specified level, the method 1000 may reduce the logical storagecapacity and thereby increase the amount of overprovisioning of thestorage drive 204.

The method 1000 then reclassifies 1008 the storage drives 204 within thestorage environment based on the determined characteristics. Forexample, if a storage drive 204 has reached a certain age, the method1000 may reclassify 1008 the storage drive 204 from performance class Ato performance class B, or from performance class B to performance classC. In another example, if a storage drive 204 has reached a certain ageor amount of wear, the method 1000 may reclassify 1008 the storage drive204 from a first writes-per-day classification to a secondwrites-per-day classification. In yet another example, if a storagedrive 204 has reached a certain age or amount of wear, the method 1000may reclassify 1008 the storage drive 204 from having a first logicalstorage capacity to having a second logical storage capacity.

The method 1000 then determines 1010 requirements of certain storagegroups (e.g., RAID arrays 304, storage tiers, storage drives 204supporting certain workloads, etc.) that contain the storage drives 204.For example, the method 1000 may determine the performance requirementsof RAID arrays 304 within the storage environment. Based on therequirements of the storage groups and the classifications of thestorage drives 204, the method 1000 reorganizes 1012 storage drives 204within the storage groups. For example, the method 1000 may attempt toreorganize 1012 storage drives 204 in RAID arrays 304 such that higherperformance RAID arrays 304 or storage tiers contain storage drives 204of a higher performance class (e.g., performance class A), and lowerperformance RAID arrays 304 or storage tiers contain storage drives 204of a lower performance class. In certain embodiments, this may beaccomplished by swapping storage drives 204 in the RAID arrays 304 orstorage tiers using a smart rebuild process that swaps data between thestorage drives 204.

Referring to FIG. 11, one embodiment of a method 1100 for reorganizingstorage drives 204 based on their performance class is illustrated. If,at step 1102, it is time to reclassify and reorganize storage drives 204within the storage environment, the method 1100 determines 1104 the ageof storage drives 204 in the storage environment. The method 1100 thenreduces 1106 the performance class of storage drives 204 whose age hasreached a designated threshold. For example, a storage drive 204 with athree-year projected lifespan may be reduced 1106 from performance classA to performance class B once it has reached one year of age. The samestorage drive 204 may be reduced 1106 from performance class B toperformance class C when it has reached two years of age.

The method 1100 then determines 1108 the requirements of various storagegroups (e.g., RAID arrays 304, storage tiers, storage drives 204supporting certain workloads, etc.) in the storage environment. Forexample, the method 1100 may determine that a first RAID array 304 orstorage tier in the storage environment requires higher performance andthus higher performance storage drives 204 and a second RAID array 304or storage tier in the storage environment can utilize lower performancestorage drives 204. Based on the requirements of the storage groups andthe characteristics of the storage drives 204, the method 1100reorganizes 1110 storage drives 204 within the storage groups. Forexample, the method 1100 may place, as much as possible, storage drives204 of the same performance class in the same storage groups. In certainembodiments, this may be accomplished by swapping storage drives 204 inthe RAID arrays 304 or storage tiers using a smart rebuild process.

In certain embodiments, the reorganization step 1110 works as follows,assuming storage drives 204 are reorganized according to theirperformance class, the storage drives 204 are classified as eitherperformance class A, B, or C, and the storage groups are RAID arrays304: The reorganization step 1110 may first generate a “count” of allstorage drives 204 in the storage environment of performance class A.The reorganization step 1110 may then find the RAID array 304 in thestorage environment with the most performance class A storage drives204. The reorganization step 1110 reduces the “count” by the number ofperformance class A storage drives 204 in the RAID array 304. Thereorganization step 1110 then swaps performance class A storage drives204 from other RAID arrays 304 into the RAID array 304 using a smartrebuild process until the RAID array 304 contains all performance classA storage drives 204. The reorganization step 1110 reduces the “count”by the number of storage drives 204 that are swapped. If the “count” iszero, then the reorganization for storage drives 204 of performanceclass A stops. Otherwise the reorganization step 1110 repeats for theRAID array 304 with the next highest number of performance class Astorage drives 204 or until the “count” goes to zero. Thisreorganization step 1110 is repeated for performance class B andperformance class C storage drives 204. The reorganization step 1110will place, as much as possible, storage drives 204 of the sameperformance class in the same RAID arrays 304.

Referring to FIG. 12, one embodiment of a method 1200 for reorganizingstorage drives based on their writes-per-day classification isillustrated. If, at step 1202, it is time to reclassify and reorganizestorage drives 204 within the storage environment, the method 1200determines 1204 the age and/or amount of overprovisioning of storagedrives 204 in the storage environment. The method 1200 then reduces 1206the writes-per-day classification of storage drives 204 whose age oramount of overprovisioning has reached a designated threshold. Forexample, a storage drive 204 may be reduced 1206 from a level 1writes-per-day classification to a level 2 writes-per-day classificationonce the storage drive 204 has reached a first age (e.g., one year) orspecified amount of overprovisioning (less than ten percentoverprovisioning, for example). Similarly, the storage drive 204 may bereduced 1206 from a level 2 writes-per-day classification to a level 3writes-per-day classification once the storage drive 204 has reached asecond age (e.g., two years) or once again reached the specified amountof overprovisioning.

The method 1200 then determines 1208 the requirements of various storagegroups (e.g., RAID arrays 304, storage tiers, storage drives 204supporting certain workloads, etc.) in the storage environment. Forexample, the method 1200 may determine that a first RAID array 304 orstorage tier in the storage environment requires higher performance andthus storage drives 204 of a higher writes-per-day classification and asecond RAID array 304 or storage tier in the storage environment canutilize storage drives 204 having a lower writes-per-day classification.Based on the requirements of the storage groups and the writes-per-dayclassifications of the storage drives 204, the method 1200 reorganizes1210 storage drives 204 within the storage groups. For example, themethod 1200 may place, as much as possible, storage drives 204 of thesame writes-per-day classification in the same storage groups. Incertain embodiments, this may be accomplished by swapping storage drives204 in the RAID arrays 304 or storage tiers using a smart rebuildprocess. In certain embodiments, the reorganization step 1210 may workin much the same way as the reorganization step 1110 described inassociation with FIG. 11.

Referring to FIG. 13, one embodiment of a method 1300 for reorganizingstorage drives based on their logical storage capacity is illustrated.If, at step 1302, it is time to reclassify and reorganize storage drives204 within the storage environment, the method 1300 determines 1304 theage of storage drives 204 in the storage environment. The method 1300then determines 1306, based on the age of the storage drives 204, anappropriate decrease in the logical storage capacity and an increase inthe amount of overprovisioning for the storage drives 204. If a storagedrive 204 contains an amount of data that exceeds what can beaccommodated in the newly determined logical storage capacity, themethod 1300 migrates 1308 the data out of the storage drive 204 toanother location. The storage drives 204 may then be reconfigured todedicate the released logical storage capacity to overprovisioning. Themethod 1300 then decreases 1310 the logical storage capacity andincreases 1310 the amount of overprovisioning in the storage drives 204in accordance with the amounts determined at step 1306.

The method 1300 then reorganizes 1310 storage drives 204 within storagegroups (e.g., RAID arrays 304, storage tiers, etc.). For example, themethod 1300 may place, as much as possible, storage drives 204 of thesame logical storage capacity in the same storage groups. In certainembodiments, this may be accomplished by swapping storage drives 204 inthe storage groups using a smart rebuild process. In certainembodiments, the reorganization step 1310 may work in much the same wayas the reorganization steps 1110, 1210 described in association withFIGS. 11 and 12.

The flowcharts and/or block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer-usable media according to variousembodiments of the present invention. In this regard, each block in theflowcharts or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the Figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustrations,and combinations of blocks in the block diagrams and/or flowchartillustrations, may be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

1. A method for dynamically altering logical storage capacity within aplurality of storage drives, the method comprising: monitoring, within astorage environment, characteristics of a plurality of storage drives,each storage drive having an amount of overprovisioning associatedtherewith; periodically performing the following: based on thecharacteristics, modifying a logical storage capacity of the storagedrives in order to alter the amount of overprovisioning, whereinmodifying the logical storage capacity comprises migrating data out ofthe storage drives in order to increase the amount of overprovisioning;and reorganizing the storage drives within various storage groups basedon the logical storage capacity.
 2. The method of claim 1, wherein thestorage groups are RAID arrays.
 3. The method of claim 1, wherein thestorage groups are storage tiers in a tiered storage environment.
 4. Themethod of claim 1, wherein the storage groups are groups of storagedrives configured to support a certain I/O workload.
 5. The method ofclaim 1, wherein monitoring characteristics comprises monitoring an ageof the storage drives.
 6. The method of claim 1, wherein monitoringcharacteristics comprises monitoring wear of the storage drives.
 7. Themethod of claim 1, wherein reorganizing the storage drives comprisesplacing, as much as possible, storage drives of the same logical storagecapacity in the same storage groups.
 8. A computer program product fordynamically altering logical storage capacity within a plurality ofstorage drives, the computer program product comprising acomputer-readable medium having computer-usable program code embodiedtherein, the computer-usable program code configured to perform thefollowing when executed by at least one processor: monitor, within astorage environment, characteristics of a plurality of storage drives,each storage drive having an amount of overprovisioning associatedtherewith; periodically perform the following: based on thecharacteristics, modify a logical storage capacity of the storage drivesin order to alter the amount of overprovisioning, wherein modifying thelogical storage capacity comprises migrating data out of the storagedrives in order to increase the amount of overprovisioning; andreorganize the storage drives within various storage groups based on thelogical storage capacity.
 9. The computer program product of claim 8,wherein the storage groups are RAID arrays.
 10. The computer programproduct of claim 8, wherein the storage groups are storage tiers in atiered storage environment.
 11. The computer program product of claim 8,wherein the storage groups are groups of storage drives configured tosupport a certain I/O workload.
 12. The computer program product ofclaim 8, wherein monitoring characteristics comprises monitoring an ageof the storage drives.
 13. The computer program product of claim 8,wherein monitoring characteristics comprises monitoring wear of thestorage drives.
 14. The computer program product of claim 8, whereinreorganizing the storage drives comprises placing, as much as possible,storage drives of the same logical storage capacity in the same storagegroups.
 15. A system for dynamically altering logical storage capacitywithin a plurality of storage drives, the system comprising: at leastone processor; at least one memory device coupled to the at least oneprocessor and storing instructions for execution on the at least oneprocessor, the instructions causing the at least one processor to:monitor, within a storage environment, characteristics of a plurality ofstorage drives, each storage drive having an amount of overprovisioningassociated therewith; periodically perform the following: based on thecharacteristics, modify a logical storage capacity of the storage drivesin order to alter the amount of overprovisioning, wherein modifying thelogical storage capacity comprises migrating data out of the storagedrives in order to increase the amount of overprovisioning; andreorganize the storage drives within various storage groups based on thelogical storage capacity.
 16. The system of claim 15, wherein thestorage groups are RAID arrays.
 17. The system of claim 15, wherein thestorage groups are storage tiers in a tiered storage environment. 18.The system of claim 15, wherein the storage groups are groups of storagedrives configured to support a certain I/O workload.
 19. The system ofclaim 15, wherein monitoring characteristics comprises monitoring atleast one of an age of the storage drives and wear of the storagedrives.
 20. The system of claim 15, wherein reorganizing the storagedrives comprises placing, as much as possible, storage drives of thesame logical storage capacity in the same storage groups.